Fujifilm X100T has a 16.0MP APS-C (23.6 x 15.8 mm ) sized CMOS X-TRANS II sensor and features EXR Processor II processor. On the other hand, Fujifilm X100 has a 12.0MP APS-C (23.6 x 15.8 mm ) sized CMOS sensor and features EXR processor.
One other difference between these two cameras that is worth mentioning is that Fujifilm X100's sensor doesn't have an anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moire occurring in certain scenes.
Below you can see the X100T and X100 sensor size comparison.
Fujifilm X100T and Fujifilm X100 have sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture. On the other hand, since Fujifilm X100 has 30% larger pixel area (30.54µm2 vs 23.33µm2) compared to Fujifilm X100T, it has larger pixel area to collect light hence potential to have less noise in low light / High ISO images.